International Journal of Comparative Psychology

Articles

• Gender Differences in Marmosets and Tamarins: Responses to Food Tasks

  • Box, Hilary;
  • Yamamoto, Maria Emilia;
  • Lopes, Fivia Araujo

  The study of behavioural gender differences among Callitrichid primates

  has been generally neglected. We describe evidence from experimental studies in

  which adult female tamarins (Saguinus) and marmosets (Callithrix) demonstrate priority

  of access to food that is spatially and temporarily restricted. Differences in behavioural

  strategies between both reproductive and non-reproductive females, and males, are

  consistent with differences between the genera in their feeding ecology and social

  organisation. They are also functionally plausible. A recent study gives preliminary

  data to show that, although mated females in family groups of common marmosets

  demonstrate priority of access to food sources, overall there are differences in

  responsiveness that may be influenced by factors such as the time of feeding, energy

  content and preference of food.

• Intra-and Inter-Specific Social Learning of a Novel Food Task in Two Species of Tamarin

  • Prescott, Mark J;
  • Buchanan-Smith, Hannah M

  Intra- and inter-specific social learning was investigated in two species of

  New World monkey, the saddle-backed tamarin {Saguinus fuscicoUis) and the redbellied

  tamarin {S. labiatus), which form stable and permanent mixed-species troops in

  the wild. We explored whether improved food acquisition, through social learning, is a

  potential advantage of mixed-species troop formation by allowing a pair of naive

  observers to watch a pair of trained demonstrators complete a novel foraging task. The

  aims of the study were (a) to determine if individuals succeeded at the task more

  quickly after having observed demonstrators, (b) to investigate whether speed of

  acquisition differed after observation of conspecific demonstrators as opposed to

  congeneric demonstrators, and (c) to compare performance between species. The

  number of trials taken by observers to succeed on the task was compared with that taken

  by naive demonstrators to succeed on the task initially. Individuals succeeded on the

  task more quickly if they had had the opportunity to watch demonstrators perform the

  task, regardless of whether the demonstrator was a conspecific or congeneric. There was

  no difference in performance between species. It is concluded that, for both species, the

  learning of a new foraging technique is facilitated by the presence of both conspecifics

  and congenerics and that the likely mechanism for this facilitation is a combination of

  stimulus enhancement and response facilitation. Social learning of this kind is discussed

  with respect its adaptive value in wild mixed-species tamarin troops.

• factors Associated with Exploration in Marmosets: Age, Gender and Hand Preference

  • Rogers, L J

  Age, hand preference and gender are shown to be associated with

  exploration behaviour performed by Callithrix jaccfius, depending on the context in

  which the marmosets are tested. When each marmoset was tested alone in a novel

  environment, hand preference had a significant effect on exploration: right-handed

  marmosets explored more actively than left-handed ones. This difference is probably

  related to hemispheric specialisation for processing novel stimuli and controlling

  emotional responses. Age and gender were found to have no significant effect on

  exploration in this context. When the marmosets were tested in the social groups and by

  placing novel objects in their home cages, both hand preference and age influenced

  approach and interaction with the stimuli, but again gender had no significant effect.

  Solving a novel problem in the home cage was influenced only by age, or related social

  dominance, and not by gender or hand preference. The implications of these results to

  behaviour of wild marmosets and other species are discussed.